Lawn treatment has become an important service industry in this country, particularly in the suburban areas where single family homes and garden apartments are numerous. A typical service unit normally utilizes a manually operated spray gun system. Such a system includes a spray gun held by the operator, a service vehicle equipped with a supply tank containing a mixture of water, fertilizer, and treatment solution such as pesticide, and a length of hose connected between the gun and the supply tank on the service vehicle.
Other lawn treatment systems are known wherein the operator carries on his person a container of pesticide or herbicide which is metered into an injection gun, mixed with the fertilizer solution from the service vehicle, and then discharged as a spray on the lawn.
The operator's job, whether handling a conventional spray gun or an injection gun, is a demanding one. It requires a great deal of manual dexterity, coordination, concentration, and care because he is applying pesticides or herbicides which have been premixed in the fertilizer solution discharged by the gun. In many instances, he is carrying on his person a container of highly toxic chemicals. The job is also fatiguing because he must manipulate the gun while literally dragging with him long stretches of hose which may be up to 300 feet in length. Operator fatigue may result in improper or excessive application of pesticide or herbicide to the lawn or to adjacent gardens, shrubs or trees, causing severe damage.